Gas centrifuge for isotope separation



Oct. 10, 1961 K. STEIMEL 3,004,158

GAS CENTRIFUGE FOR ISOTOPE SEPARATION Filed Oct. 29, 1958 6 Sheets-Sheet 2 F /'g. 2 H A II M 37 H Y 25 33 37 3 I 1 I, J 37 I r l l 22 I I I 20 38 VII, l i 3a 37 I 4/ +2 29 2/ fm emon' KARL STE/MEL By Voufinm, gi-m'ubz,

xlffomqys Oct. 10, 1961 K. STEIMEL 3,004,158

GAS CENTRIFUGE FOR ISOTOPE SEPARATION Filed Oct; 29, 1958 6 Sheets-Sheet 3 KARL STf/MEL by W p m A/lvrneys Oct. 10, 1961 K. STEIMEL GAS CENTRIFUGE FOR ISOTOPE SEPARATION 6 Sheets-Sheet 4 Filed Oct. 29, 1958 [river/for: KA RL STE/MEL by W am Aflomqvs Oct. 10, 1961 Filed Oct. 29, 1958 K. STEIMEL 3,004,158

GAS CENTRIFUGE FOR ISOTOPE SEPARATION 6 Sheets-Sheet 5 IFARL STE/MEL By W ,amm,

A/bmeys Oct. 10, 1961 K. STEIMEL 3,004,158

GAS CENTRIFUGE FOR ISOTOPE SEPARATION Filed Oct. 29, 1958 6 Sheets-Sheet 6 42 m I33 "A KARL STE/MEL By W p M //#omey rates atent #Ohice .3,tlil-i,l53 GAS CENTREFUGE FfiR HSUTQPE EEEPARATIGN Karl Steirnel, Konigstein, Germany, assignor "to Licentia Patent-Versesltungs-Gnr.all Hambrug, Germany Filed Get. 29, 1958, Ser. No. 770,475 Claims priority, application Germany Get. 30, .1957 18 Claims. (fill. 250-413) The invention relates to a gas centrifuge for the separation of isotopes.

It is an object of my invention to provide a new type of gas centrifuge for isotope separation, which permits to attain much higher circumferential velocities, and consequently much higher yield rates than the conventional gas centrifuges, while at the same time requiring far less power for ionization energies than the known electromagnetic mass separators.

Mechanical gas centrifuges are already known for this purpose. One such mechanical gas centrifuge, as described for example as a basic form in the book entitled Ubcr Gaszentrifugen by K. .Beyerle, W. .Groth,.P. Harteek and H. Jensen, published by Verlag (Ihernie G.rn.b.H., Weinheim/Bergstrasse, Germany, in 1950, consists essentially of a centrifugal drum driven at -a high speed of rotation of a motor. During the rotation of the drum the centrifugal force acts on a gas mass introduced into the centrifugal drum andcauses a concentration of the heavy isotope towards the wall of the drum and a corresponding concentration of the light isotope towards the axis of the drum.

The practical utilization of this separating effect .is dependent upon the attainable circumferential velocity of the rotating gas mass. Apart from the accompanying operational difllculties occurring when using high circumferential velocities an absolute velocity limit 'is set bythe rupture limit of the drum material. The gas centrifuge according to the invention is not subject to this linritation. It also possesses advantage in other respects.

Furthermore, it is known to separate isotopes by means of an electromagnetic mass separator symmetrical with respect to rotation, as described by L. 'P. Smith, W. 'E.

"Parkins and A. T. Forrester in the publication Physical V Review 72 ("1947), No. 11, pages 989 to 1002, and in which the substance, the isotopes of which are to be separated, is taken from a source of ions in the 'form of an ion stream. The ions are accelerated in an evacuated space by means of a high voltage device and deflected by a'magnetic field to a difierent degree according to their mass and each ion is sedirnente'd in a determined zone of a collector according to its mass. A condition for achievin g this result, is, however, that all ions of the same mass are present in one and the same ionization stage and that the gas pressure prevailing in the deflecting space is so low thatiion beams can develop with a path which is not disturbed by the thermal movement of the gas particles. With these mass separators, however, only entirely unsatisfactory yields of the various isotopes can be obtained particularly in the case of elements having high mass numbers. The mass throughput of this "arrangernent is moreover extremely small already "on 'account of the requirement for the complete conversion into ions of the substance quantity to'be separated.

The invention consists in that a stationary drum receives a gas mass at a pressure at which the mean number of collisions of the gasparticlesis greater'than double the frequency of the periodicity of the "movement'of the gas ion in a magnetic field, and that in-the gas space an electric current of a gas discharge "and a magnetic field standing at right angles thereto with atleast one non-vanishing component are arrangedaxially'symmetrical "to the axis of the drum.

A homogeneous magnetic field parallel to the .drum taxis and an electric current extending in a plane perpen- :dicular tothe drum axis represent an example of an arrangement of-a magnetic field and an electric current of a gas discharge axially symmetricalto the drum axis of a circular cylindrical drum. 'In this arrangement the rotation symmetrical magneticlield in its entirety stands perpendicular to the electric current.

In the gas centrifugeiaccording to the invention a mo- .ment of rotation is exerted on the gas under a certain ,gas pressure in the drum by meansof the gas discharge carried out in this arrangement, whichrnoment imparts rotary :motion to the ,gas .mass. Such an arrangement for producing a rotary motion canbe described as a unipolar machine.

With the gas centrifuge according to the iuventioncircumferential velocities of the rotating gas mass :can be attained which are many times as great as those in the known gas centrifuge with a rotary drum. This considerable increase in the circumferential velocity enables .a great increasein the utilization of the separating elfect of the gas centrifuge.

Animportant advantage of .the ,gas centrifuge according to the invention-over thelmown electromagneticmass separator is that in a gas centrifuge according to the invention only a fraction .of the existing gas particles -'of the gas mass to be separated need beionized because not only the gas ion component but'the whole gas mass of the drumissubjected to the separating eifect.

The formation of a .rotary gas current through a dischargecurrent perpendicular to the direction of a magnetic field is known per se. See the article entitled Supersonic Wind at .Low Pressures Produced by .Arc in Magnetic Biol :by (3. ;Early and W. :6. .Dow,

publishedin theperiodical Physical Review 7-9 (1959 page 186, in which an arrangement is described-for pro- .ducing .'a wind stream with supersonic velocity.

The knownprinciple of imparting rotary motion .to .a gas .mass by :means of :a discharge current ionizing ;a

;.p'ortion of thegasparticles .and'of a magnetic field with at least one .non-vanishingcomponent standing perpendicular to the discharge current, is, according to the-invention, employed for isotope separation, utilizing the centrifugal force in a gas mass to which rotary motion is electromagneticallyimparted in this fashion.

In the arrangement .according to the invention, the drum contains a ;gas at ;-a pressure which is preferably :50 high that the mean free path :of the gas particles is small ascompared with .the discharge path, beingpreferably by .two to four orders-of magnitude smaller. Thus the throughput of the gas centrifuge according to the invention can be high.

The drum-receiving the gas :to be separated preferably hasa radius which is larger, preferably byseveralorders of magnitude than the diameter-of the circular motion orainovement containing a circular-path of thegasions :in a homogeneous .magnetic field which with at "least one non-vanishing component is perpendicular .to the :direction of the velocityiofthe gas ion.

The effect of :the gas centrifuge according :to thetinvention is not confined to the embodiment that the "gas discharge burnszradially andithe magnetic fieldiisiinraxial direction. The two directions can be reversediorlielina different position providing the condition of standing perpendicular andt-he requirement of axial symmetrical arrangement to ,the drum axisaremet at leastapproximately.

,For example anarrarrgement of a.rotation symmetrical, axiaL-magnetic field and a funnel-shaped stream surface of the gas 'clisc'harge,wherein theaxis .of the funnel coincides with the axis of the drum, is suitable 'forlthe construction 'of a gas 'centr-fuge "according -to 'the invention,

3. because the magnetic field has a component which stands at right angles to the direction of the electric current and the value of which is not zero.

According to an advantageous embodiment of the invention, a supplementary separating eifect can be attained by giving the electrodes of the electric gas discharge such polarity that the direction of the component of the movement of the charge carriers of the discharge current radial to the drum axis is directed away from the drum axis.

Another preferred embodiment of the invention is a gas centrifuge the gas feed of which is at such a distance from the drum axis that at the gas feed the same density ratios of the isotopes prevail in the rotating gas mass as in the gas to be introduced.

According to another embodiment of the invention, at least one of the electrodes of the gas discharge is divided into segments and in each of the conductors leading to the segments there is a series resistance or/ and an impedance coil.

With this arrangement, the tendency of the electrical discharge to constrict and rotate in the magnetic field like 'the spoke of a wheel, especially if the gas pressure is not maintained at its'maximum, can be prevented.

By the use of such an arrangement for a gas centrifuge it is possible to attain a uniform distribution of the electric current of the discharge on the entire current space. If the current in one of the leads to the segments threatens to drop owing to a failure in the discharge current space, the voltage decreases on the series resistance in this lead and the voltage rises on the particular segment and draws a greater current to this segment. The homogenizing of the electric discharge is also advantageous because, through the uniformity of the electric discharge, a further intensification of the effect of the gas centrifuge can be attained.

The construction of the electrode arrangement for the gas discharge is not restricted to the factor that the gas discharge burns radially and the magnetic field is axially directed.

The magnetic field may be in radial (axially symmetrical) direction and the electric current of the gas discharge may flow in axial direction, in fact any combination of the magnetic field and current direction may be chosen, provided the direction of the magnetic field and electric current are substantially at right angles to each other and axial symmetry of the whole arrangement is present.

The invention will be still better understood from the description thereof given hereinafter in connection with the accompanying drawings, in which:

FIGURE 1 is a schematic, partially sectional view in perspective of an embodiment of a gas centrifuge according to my invention, comprising a radially extending electrical field and a magnetic field intersecting the former perpendicularly thereto;

FIGURE 2 is a perspective, partially schematic view of another preferred embodiment of the gas centrifuge according to the invention;

FIGURE 3 shows schematically another arrangement of the electrodes in a gas centrifuge similar to that shown in FIGURE 2;

FIGURE 4 shows schematically a difierent electrode arrangement of a gas centrifuge according to the invention;

FIGURE 5 is a perspective schematic view of yet another embodiment of the gas centrifuge according to the invention;

FIGURE 6 shows a further electrical arrangement for connecting the electrodes of a gas centrifuge similar to that shown in FIGURE 5, and

FIGURE 7 shows yet another electrical arrangement for connecting the electrodes of a gas centrifuge similar to that shown in FIGURE 5;

FIGURE 8 illustrates schematically and partially in sectional view a further embodiment of a gas centrifuge 4 according to the invention, in which a magnetic field extends in radial direction and is intersected by an electric field extending perpendicularly thereto.

In FIGURE 1, the stationary circular cylindrical drum 1 is charged with a gas mass composed of the isotope mixture to be separated. In this gas mass an electric discharge with current radially symmetrical to the drum axis A is maintained between a peripheral circular cylindrical shell-shaped electrode 2 concentric to the drum axis A and two central circular ring-disc-shaped electrodes 3 and 4 also concentric to the drum axis A. The electrodes 2, 3 and 4 are connected to a source of current by an electric lead 5 and a branched lead 6, the/electrode 2 being, for example, connected to the negative pole and the electrodes 3 and 4 to the positive pole. By means of two circular ring-shaped magnet poles 7 and 8 concentric to the drum axis A, a magnetic field H is produced axially symmetrical to the drum axis A and extending perpendicular to the radially flowing discharge current j and, if the magnet pole 7 is the N-pole and the magnet 8 the S-pole, this field passes in the direction from the magnet pole 7 to the magnet pole 8.

By means of the gas discharge described in this arrangement a movement of rotation is impressed on the gas contained at a certain pressure in the drum and produces a rotary movement of the gas mass about the drum axis.

If, for example, the gas in the drum has a pressure which is so high that the mean impact number of the gas particles is greater than twice the frequency of the periodicity of the cycloidal movement which a gas ion of the gas mass would carry out in the magnetic field without thermic collisions with the other gas particles, the gas ions of the discharge cur-rent will have carried out at each collision on an average less than half a revolution of a period of the cycloidal movement. Therefore the gas ions on collision transmit to the impacted particle an impulse Which on account of the tangential component of the field forces acting on the gas ions, has a tangential component which determines on the average a direction the sense of which is coordinated to the drum axis by a left hand screw in as far as the discharge current is composed of positive gas ions and it has been decided that the direction of the drum axis is to be in the same sense as the direction of the magnetic field, and thus, in the case of the rotation symmetrical arrangement of magnetic field and electric discharge current, allows a rotary movement.

To attain the greatest possible effect of the gas ion impacts in the direction of the desired movement of the entire gas mass, the gas pressure, the magnetic field and the electric field are so tuned to each other than the mean free path is smaller than half the circumference of a Larrnor circle of a gas ion.

Owing to the centrifugal force generated in the rotating gas mass the heavy isotope concentrates on the drum wall 9 and the light isotope towards the drum axis A. Therefore a quantity of gas enriched with heavy isotope can be drawn ofi for example at a circular ring-shaped aperture 10 and a quantity of gas enriched with light isotope at a circular disc-shaped aperture 11 by sucking oil the isotope mixture at these points through the gas conduits 12 and 13 by means. of pumps 14 and 15 respectively. The gas mass is preferably introduced at the point of the cylindrical gas space Where the same density proportions of the isotopes prevail in the rotating gas mixture as in the gas introduced. The two magnet poles 7 and 8 can each be divided by means of a gap 16 and 17 respectively, and these annular gaps connected to a pump 19 by a branched gas conduit 18.

When operating the gas centrifuge according to the invention the conditions for the gas discharge can be so chosen that the electric field intensity E acting on the charge carriers of the discharge current 1' acts with at least a portion of its amplitude in the same sense as the centrifugal force Z acting on all the gas particles.

Such an chest, is attained by poling the electrodes 2, 3 and 4 of the discharge so that the direction of movement radial to the drum axis A or .of the movement component of the charge carriers of the discharge current i is away from the drum axis A. In the present example this is the case if, with a discharge current composed at least mainly of negative charge carriers, the peripheral electrode 2 is positive in relation to the central electrodes. 3 and 4, whereas with a discharge current i composed at least mainly of positive charge, carriers G9, it is negative in relation to the central electrodes 3 and 4. The electrically charged particles ofv the gas discharge, under a gas pressure which is higher than a certain minimum, describe in the magnetic. field H between the collisions with other gas particles circular paths having a radius proportional to the square root of their mass.

Therefore, during the current transport in radial dis rection, the heavier particles are deflected with greater radius than the lighter particles, which result in an additional separating effect.

In the embodiment of the invention illustrated in FIG URE 2, the electrode arrangement for the electric gas discharge consists of a peripheral circular cylindrical shell-shaped electrode 20 which, according to the invention, is divided along its circumference into, for example, eight pieces 21'. to 28, that is, into segments, in the current lead of each of which a series-resistance 37 and an impedance 38 are located, and also of a central elec trode composed of circular ring-shaped discs 39 and 40 which are parallel to each other and concentric to the symmetry axis A These discs are arranged symmetn'cally to a plane perpendicular to the symmetry axis A in which the discharge current 1' flows from the central electrode parts 39 and 40 to the electrode 20 divided into segments. The two central electrode parts 39 and 49 are connected by means of the branched lead 41, for example to the negative pole of a source of potential and the segments 21 to 28 of the peripheral electrode 20 by means of their leads 29 and 36 via the current lead 42 to the positive pole.

The magnetic field H is produced by the two circular ring-shaped magnets with the poles 44 and 45, which magnets are concentric to the symmetry axis A and provided with a circular ring-shaped gap 43, and lies perpendicular to the radially flowing discharge current j.

This arrangement enables particularly favorable stabilization of the electric discharge, whereby theperipheral circular cylindrical shell-shaped electrode 26, owing to its subdivision into segments 21 and 28 and the construction of the current leads to the segments by the introduction of'resistances 37 and impedances 38 therein, brings about an azimuthal homogenization. Further more the central circular ring-disc-shaped electrode parts 39 and 40, owing to their symmetrical position in relation to the discharge current plane perpendicular to the symmetry axis A, and series resistances 37 and impedances 38, arranged in the current leads to the two electrode parts 39 and 40, cause axial uniformity of the current distribution of the gas discharge.

Another electrode arrangement is illustrated schematically in FIGURE 3. This figure shows in an elevation parallel to the magnetic field H a peripheral electrode 20 divided into segments 21 to 28 and a central electrode consisting of two circular ring discs 39 and 4b. In the examples illustrated, a resistance 37 is arranged in each of the current leads 2%, to 36 to the segments 21 to 28. These current leads 29 to 36 each carrying a series resistance 37 are connected with the positive pole of a source of potential by a lead 46, whereas the central electrode 39, 40 is connected to the negative pole of the source of potential by a lead 49.

FIGURE 4 shows an example of an electrode arrangement in which impedances 47 are introduced in the current leads 29 to 36 to the segments 21 to 28 of the peripheral electrode 20. These leads 29 to 36 are connected, for example, to the negative pole of a source of current by the lead 48, the central electrode 39, 40 being connected to the positive pole by the lead49.

Another advantageous embodiment of the invention consists of an electrode arrangement such as shown partly in perspective and schematically in FIGURE 5. It has a peripheral electrode 50, for example of circular cylindrical shell-shape, and a ring-disc-shaped central electrode 51. which is divided into segments 52 to 59 and in each of the current leads 60 to 67 a series resistance 68 and an impedance coil 69 are arranged. The magnetic field H lies perpendicular to the current i flowing radiallybetween the central electrode 51 and the peripheral elee trode 50 and can be generated by two circular ring-shaped magnet poles such as shown in FIGURE 1, arranged concentrically to the symmetry axis A. As can be seen from FIGURE 5, a favorable construction of the electrode arrangement can also be attained in that theeleetrode arrangement has, instead of a single central ringdisc-shaped electrode 5-1, two central ring-disc-shaped, parallel, concentric electrodes '51 and 71 divided into segments 52 to 59 and '71 to 78 respectively and arranged symmetrically to the discharge current plane perpendicular to the symmetry axis A, a series resistance 58 and an impedance 69 being located in each of the current leads 6% to 67 and 7h to 86 respectively leading to the two central electrodesel and 7h.

FIGURES 6 and 7 show two further tavorableexamples for the construction of the leads 87 to- $2 of the segments as to 98 of the central electrode 99 in FIGURE 6' and the leads 1% to MW of the segments 11% to-119 of the central electrode 129 in FIGURE 7. The electrode arrangement in both examples comprises a peripheral, cylindrical shell-shaped electrode 50' which is concentric with the symmetry axis A and defines the planein which the discharge current i flows in the case of the present rotation symmetrical arrangement of the discharge current j and axial magnetic field H. The central circular ring-shaped electrode 99 or 12% divided into segments, 93 to 93 and lltl to 119 respectively, is concentric to, the symmetry axis A and lies in the discharge current plane extending through the peripheral electrode 56 and stand ing perpendicular to the symmetry axis A. Instead of a single central electrode 99 or 120, two central ring-disg shaped electrodes: can be used arranged symmetrically to the discharge current plane perpendicular to the symmetry axis A and divided into segments. In each of these examples the arrangement of the leads shown in EIG; URES 6 and 7 can be employed. FIGURE 6; shows an example in which a series-resistance 6? is located in each of the feed wires 87 to 2 and these wires are connected by the lead-in wire 121 to one of the poles: of the source of current, In the example illustrated in FIGURE 7 an impedance 69 1's located in each of the feed wires 1% to 10-9. These wires are connected to one pole of the source of current by a current feed wire 122.

FIGURE 8 shows an advantageous arrangement in which the magnetic field is in radial direction and rotation symmetry. This arrangement has two paralleldiscshaped, preferably ring-disc-shaped electrodes 123 and 124- concentric to the symmetry axis A, both these electrodes being divided into segments 125 to 132, that is into circular arc-shaped parts. A series-resistance 141 and an impedance 7.4-2; are connected in series in each of the leads 136 to 144i to the segments 125 to 132. The leads 133 to 149 to the segments of the electrode 123 are connected to the positive pole of a source of potential by a lead-in wire 143 and the leads to the segments of the electrode 124 to the negative pole of the source of potential by a lead-in wire 144.

In the arrangement with a radial magnetic field in. a plane perpendicular to the symmetry axis A, thisv mag; netic field may be generated, for example, by amagnet 151 composed of several sector-shaped parts to 150. The magnetic field H is directed radially outwards from the symmetry axis A when the magnet poles 152 to 157 are N-poles and the magnet poles 158 to 163 S-poles. The gas mass in this arrangement of discharge current i and magnetic field H is rotated about the symmetry axis A in such a manner that the movement in the left half of the figure takes place away from the viewer and in the right half towards the viewer, in as far as positive charge'carriers form the discharge current at least to a predominant extent.

Circular ring-shaped gaps 16-4 and 165 can advantageously be provided in both electrodes for feeding the gas. In the example illustrated similar apertures can be provided in the magnet 151 for the introduction and drawing off the gas.

In the gas centrifuge according to the invention it is possible to obtain a multiplication of the separation sheet by connecting several separating spaces in series as in known gas centrifuges. Details of the construction of such series connection of separate gas chambers and the manner of operating the same are described for example in the above-mentioned book Uber Gaszentrifugen by K. Beyerle. A series-connection for a gas centrifuge according to the invention is developed from the single chamber gas centrifuge by subdividing the centrifugal drum in axial direction and constructing each chamber as a gas centrifuge with stationary drum with. a magnetic field arranged therein axially symmetrical to the drum axis and electric gas discharge burning perpendicularly to the direction of this field. The development of the gas centrifuge according to the invention into further built-up arrangements can be carried out according to the method of series-connection in a manner similar to that used for other combinations of separate stages which, for example, are also mentioned in the above book Uber Gaszentrifugen by K. Beyerle and elsewhere.

Example wherein: P=the pressure =mean impact number v=dynamic viscosity.

The example is to be carried out with uraninumhexafluoride UF having the molecular weight of 352 based on uranium atomic weight of 238.

Uraniumhexafluoride is evaporated at atmospheric temperature and introduced through conduit 18 and the angular gaps l6 and 17 into the separation chamber of a centrifuge embodiment as shown in FIGURE 1.

The magnetic field strength is chosen at 5,000 gauss.

Assuming that one gas ion alone moves in a magnetic field of the magnetic field strength of 5,000 gauss withouthaving collisions with other gas particles, then the num ber of revolutions of the periodicity of the path of the gas ion can be calculated from the known Larmor frequency, for the case of an UP ion of molecular weight 352 the said number is 357,000 revolutions per second.

The pressure of the gas in the centrifuge must therefore be so chosen that the mean number of collisions of the UP particles is greater than twice the aforesaid number of revolutions. This condition is fulfilled when the gas pressure is greater than a minimum pressure having a minimum means impact number, which is equal the said number of revolutions.

From the above formula for gas pressure, and using for the calculation the viscosity of air (v=l80 micropoises) therefore a minimum pressure of 0.1 Torr can be calculated. Taking into account the higher viscosity of uraniumhexafluoride and in order to operate with a safety factor, UP is introduced into the separating chamber at such a rate that a pressure of 20 Torr is attained, i.e. approximately 200 times the above calculated minimum pressure required for making operation of the centrifuge possible.

The higher pressure of 20 Torrs also offers the advantage of a higher yield rate of the centrifuge.

The upper theoretical pressure limit when operating at room temperature is the vapor pressure of UP which is p =l20 TOI'I'S.

The voltage applied between electrodes 2, 3 and 4 is maintained above the ignition voltage for gaseous UF at the pressure of 20 Torrs. The point at which ignition voltage is reached is easily controlled by observing the firing of the gas discharge.

The moment of rotation to which the uraniumhexafluoride gas in the apparatus of FIGURE 1 is subjected leads to a circumferential velocity of the gas particles in the zone of the annular inlet gaps l6 and 17 of about 132,000 centimeters per second, i.e. more than four times the speed of sound in air.

In the rotating uraniumhexafluoride gas, the UF molecules containing the lighter isotope U which latter is present in the isotope mixture of the element and practically also in a still untreated hexafluoride, only at the rate of 0.72% by weight, are accumulated in the zone about the drum axis A-A. The heavier UF particles containing U are concentrated in the peripheral zones of the separating chamber.

Therefore, while the ratio of concentrations of heavy to light UF at the inlet gaps 16, 17 is, for instance, 137, namely if UF was not previously isotope-separated, the ratio of concentrations of U F :U F at the drum axis soon attains the value of 47. This corersponds to an increase of the share of the lighter uraniumhexafluoride U F in the total UF gas mass from initially 0.72% to 2.06% by weight.

For the sake of comparison there shall be mentioned that in a conventional mechanical gas centrifuge operated at a maximum speed of 50,000 r.p.m. the enrichment of U F in the treated uraniumhexafiuoride is only from 0.72 to 0.77% by weight, i.e. only 0.05% increase over the initial value.

The distance of the gas inlet (openings of inlet gaps 16 and 17 into the central chamber) from the drum axis A.-A determines together with the circumferential velocities to be attained, the dimensions to be given to drum 1. This drum radius should exceed that distance.

If, for instance, the aforesaid distance is 18 centimeters, the drum radius may be 20 centimeters. In the latter case, the number of revolutions of the gas mass based on the aforesaid circumferential velocity of 132,000 centimeters per second and on the aforesaid distance of 18 centimeters shows that the number of revolutions per minute is approximately 70,000. In a centrifuge having the same dimensions as the known mechanical centrifuges, namely about 6 centimeters, the above circumferential velocity would correspond to a speed of more than 200,000 rpm.

It will be understood that this invention is susceptible to modification in order to adapt it to diiierent usages and conditions, and, accordingly, it is desired to comprehend such modifications within this invention as may fall within the scope of the appended claims.

What I claim is:

1. In a process for separating gases having at least two molecules of different masses therein, by centrifugation of said gas in a drum, the improvement which comprises maintaining said gas at a pressure at which the mean number of collisions of the gas particles is greater than twice the frequency of the periodicity of the hypotheti cal motion of a gas ion moving singly in an electric field of the same direction as the electric field accompanied with the electric current in said drum as utilized in the the process and in a magnetic field of the same direction and of the same intensity as the magnetic field in said drum as utilized in the process and rotating said gas by forces developed from producing an electric current of a gas discharge and a magnetic field disposed with at least one non-vanishing component substantially perpendicularly to said electric current, the combination of electric current and magnetic field being arranged axially symmetrically relative to the axis of said drum, whereby exceedingly high velocities of the gas mass are obtained resulting in much higher centrifugation efliciencies than possible by a mechanical centrifuge.

2. The process of claim 1, wherein the gas to be separated is comprised of isotopes.

3. The process of claim 1, wherein the centrifugation is conducted in a drum, characterized in that the radius of said drum is greater by at least one order of magnitude than the diameter of a hypothetical movement comprising a circular path of a gas ion moving singly in an electric field of the same direction and of the same intensity as the electric field accompanied with the electric current in said drum as utilized in the process and in a magnetic field of the same direction and of the same intensity as the magnetic field in said drum as utilized in the process.

4. A gas centrifuge, comprising in combination: a drum; electrode means inside said drum for producing in said drum an electric current of a gas discharge; means for producing in said drum a magnetic field disposed with at least one non-vanishing component perpendicularly relative to said electric current; the combination of said means for producing said electric current of a gas discharge and of said means for producing said magnetic field being arranged axially symmetrically relative to the axis of said drum; gas feed means connected to said drum for supplying to said drum a gas mass at a pressure at which the mean number of collisions of the gas particles is greater than twice the frequency of the pe riodicity of the hypothetical motion of a gas ion moving singly in an electric field of the same direction as the electric field accompanied with said electric current in said drum and in a magnetic field of the same direction and of the same intensity as said magnetic field in said drum; gas outlet means; whereby said gas mass in said drum is given a rotary motion by the combined elfects of the electric current and magnetic field.

S. The gas centrifuge according to claim 4, characterized in that the radius of said drum is greater by at least one order of magnitude than the diameter of a hypothetical movement comprising a circular path of a gas ion moving singly in an electric field of the same direction and of the same intensity as the electric field accompanied with said electric current in said drum and in a magnetic field of the same direction and of the same intensity as said magnetic field in said drum.

6. The gas centrifuge according to claim 4, characterized in that the distance of the gas feed from the drum axis is such that at the gas feed the same density proportion of the isotopes prevails in the rotating gas mass as in the gas to be fed.

7. The gas centrifuge according to claim 4, characterized by having the magnetic field axially symmetrical to the drum axis, of ring-shape, and concentric to the drum axis, and having the electrode means comprising a peripheral cylinder-shell-shaped electrode axially symmetrical to the drum axis, and two central, ring-disc-shaped electrodes concentric to the drum axis.

8. The gas centrifuge according to claim 4, characterized by a subdivision of each of two magnetic poles producing the magnetic field, by an annular gap for feeding the gas.

9. The gas centrifuge according to claim 4, characterized in that the polarity of the electrodes of the electric gas discharge is such that the direction of the movement components of the charge carriers of the discharge current which is radial to the drum axis, points away from the drum axis.

10. The gas centrifuge according to claim 9, characterized by a peripheral electrode positive in relation to a central electrode in the case of a discharge current composed at least predominantly of negative charge carriers.

11. The gas centrifuge according to claim 9, characterized by a peripheral electrode negative in relation to a central electrode in the case of a discharge current composed at least predominantly of positive charge carriers.

12. The gas centrifuge according to claim 4 characterized in that at least one of the electrode means of the gas discharge is divided into segments and in each of the current leads to these segments at least one impedance means selected from the group consisting of series-resistance and impedance coil is arranged.

13. The gas centrifuge according to claim 12, characterized in that the electrode means comprises a cylindrical shell-shaped el ctrode, which is divided into segments.

14. The gas centrifuge according to claim 12, characterized in that the electrode means comprises a ringdisc-shaped electrode, which is divided into segments.

15. The gas centrifuge according to claim 12, characterized in that the electrode arrangement comprises a pcripheral cylinder-shell-shaped electrode and two central ring-disc-shaped, parallel, concentric electrodes divided into segments and arranged symmetrically to a plane extending perpendicularly to the symmetry axis, and that in each of the current leads to the two central electrodes at least one impedance means selected from the group consisting of series-resistance and impedance coil is located.

16. The gas centrifuge according to claim 12, characterized in that the electrode arrangement comprises two parallel, disc-shaped electrodes concentric to the symmetry axis and both electrodes are divided into segments.

17. The gas centrifuge according to claim 12, characterized in that the electrode means comprises a peripheral electrode divided into segments and central disc or ring-disc-shaped electrodes parallel to each other and concentric to the symmetry axis, and in each of the current leads at least one impedance means selected from the group consisting of series-resistance and impedance coil is located.

18. The gas centrifuge according to claim 17, characterized in that the central disc or ring-disc-shaped electrodes are arranged symmetrically to a plane extending perpendicular to the symmetry axis, whereby in this plane the discharge current runs perpendicularly to at least one non-vanishing component of the magnetic field No references cited. 

